1. Field of Disclosure
The present disclosure of invention relates to a sound wave metamaterial, and more specifically the present disclosure of invention relates to a sound wave metamaterial amplifying a sound wave using a resonance.
2. Description of Related Technology
Metamaterial is an imaginary material having a meta atom periodically arranged. Here, the meta atom is designed by a metal or a dielectric material having a small size much less than a wavelength. The metamaterial does not exist in the natural world, and is artificially made to have predetermined characteristics. For example, the metamaterial has a density higher than an air around the metamaterial but refracts a light to be far from a normal vector, which is called as negative refractive index. After Sir J. Pendry published a paper (PRL, 1999) in which a super lens may be realized by the material having the negative refractive index, the metamaterial is raised be one of the material to realize the invisible cloaking. Using transformation optics, the so-called invisible cloaking may be realized only theoretically, because 3-dimensional metamaterial is hard to be realized (until now 2-dimensional metamaterial is to be realized but having a very small size such as a several billion of the size of a postage stamp) and energy consumption of the metal is very high in a range of the visible wavelength. Until now, the invisible cloaking is experimentally realized in a range of the microwave (GHz).
An artificial atom (a meta atom) included in the metamaterial has predetermined characteristics in response to an electromagnetic wave or a sound wave applied to the metamaterial.
Accordingly, the metamaterial may be designed or composed to have arbitrary effective refractive index or an arbitrary effective material coefficient which does not exist in the natural world. Thus, the metamaterial causes new phenomena such as, a subwavelength focusing, a negative refraction, an extraordinary transmission and the invisible cloaking.
Nowadays, the studies are focused on fabricating various kinds of meta devices using the metamaterial or combining the metamaterial with various kinds of material like Graphene (Lee et al. Nature Materials, 2012), rather than imaging the wavelength using the metamaterial having the negative refractive index.
Korean laid-open patent application No. 10-2013-0105358 discloses a coil-based artificial atom of the metamaterial, the metamaterial having the same and a device having the same.
Prior art: Korean laid-open patent application No. 10-2013-0105358 (laid-open: Sep. 25, 2013.)